Cambodia broke ground on a new Chinese-funded hydropower dam in Koh Kong province on Tuesday, despite warnings from conservation groups of a heavy impact to the surrounding environment.

The $495 million dam, which China Huandian Corporation will control in a build-operate-transfer scheme for 35 years, is expect to produce 338 megawatts by 2015. NGO Forum, a group of organizations, has called the project “outdated, expensive and risky.” Other critics say the negative impacts of the dams outweigh the benefits.

Prime Minister Hun Sen has called concerns over the dam “extremist.”

“Is there any development that doesn’t have an impact on the environment and natural resources,” he said in a speech. “Please provide a reasonable response. If we can reduce our dependence on petroleum, oil or gasoline, our energy security will be ensured.”

At least five Chinese companies are investing in dam projects—in the provinces of Kampong Speu, Kampot, Koh Kong and Pursat and along the Mekong river.

Hun Sen said he expects power to flow from different projects by the end of 2011, and into 2012, 2013 and 2015.